• Tuesday, June 22nd - Sunday, June 27th:  Banding took place on five days this week and 93 birds of 22 species were banded, five of which were new for the summer season.  Randi Gerrish, Dan Hinnebusch, Mike Lohr, Jake Mohlmann, Felicity Newell, and Josh Van Buskirk all helped with banding this week.

• A few weeks ago we posted photos and discussion of physiological breeding evidence in males and females (i.e., presence of a brood patch and/or cloacal protuberance).  This week, we recaptured a Yellow Warbler that was refeathering her B.P. and thought that it would make a good follow up photo with the  progression of the breeding season.

• We frequently discuss molt on the website, in particular wing molt and its usefulness in determining the age of birds in the hand.  The second year (SY) female Yellow Warbler's wing pictured below, however, gave us reason for a different molt discussion--the "ABC's" of why birds molt in the first place.  All birds undergo at least one molt a year, the prebasic molt (i.e. post breeding or "fall" molt), during which adults will replace every feather on their body.  The main function of the prebasic molt is to renew worn and faded plumage.  In the photo below, this Yellow Warbler is undergoing her prebasic molt with primaries 1-6 (the shorter, blacker feathers in the middle counted from left to right; primary six is a "pin feather" not visible in the photo) growing in along with their corresponding primary coverts (the row of small feathers above the primaries).  Compare with the outer three primaries and corresponding coverts which show a stark contrast, being very faded and abraded.  The breeding season, in particular, can be stressful on feathers because they get easily worn with repeated trips through brush and trees to feed young.  Thus, the prebasic molt is of great importance in replacing these very worn and structurally weakened feathers with fresh, unworn and functionally stronger ones before fall migration.

• On Saturday, June 26th, we captured our second hatch year (HY) Ovenbird, this one a little older and beginning to replace its juvenal greater coverts and alula with first basic plumage (a molt limit in the making)!  This bird had dropped all greater coverts but two, skipped the carpal covert, and was molting in the first alula feather (which follows along with where we usually see molt limits in HY/SY warblers, between the first two alula feathers).

• The bottom photo shows the remaining juvenal streaked feathers of the scapular and back.  It is unlikely that the Ovenbird can be confused with any other warbler.  Taxonomically, it is related to the Northern Waterthrush and Louisiana Waterthrush, all in the Seiurus genus.  Dr. Kenneth C. Parkes, retired Senior Curator for the Section of Birds at Carnegie Museum has questioned this taxonomic relationship, however, suggesting the waterthrushes and Ovenbird might more appropriately be considered as separate genera (Dr. Parkes' view is cited as such in Dunn and Garrett's Warblers in the Peterson Field Guide series, which is one of the most thoroughly researched and well written works ever on this popular group of birds).


As a leading expert on the sequences of molts and plumages in birds, Dr. Parkes argues that, in addition to differing in aspects of behavior, locomotion, and vocalizations, there are evolutionarily significant differences in juvenal plumage and in the length of retention of that plumage between the Ovenbird and Waterthrushes.  The streaked dorsal juvenal plumage of the Ovenbird is unique to this species in the genus.  Juvenal waterthrushes resemble adults in plumage except for more loosely textured and unstructured feathers (note the unstructured upper tail coverts on the Ovenbird in the bottom photo).  The bird in the photo below will retain the streaked plumage until it completes its first basic molt, probably within about two more weeks, at which time it will then fully resemble an adult with a uniformly olive back.  At this writing, on 3 July, we actually have just caught a late-hatched Louisiana Waterthrush in full juvenal plumage, which we will post as a comparison with this Ovenbird the next time we update the website.

• Finally, on Sunday, the bird in the photos below (consider the first two images as a quiz--it isn't identified until the text below the second picture) made our final banding day for the week a success.

,.

• .This hatching year (HY) female Cerulean Warbler had completed its first prebasic molt except for a few body feathers still partly in sheath (a couple of these visible on top of its in the photos above).  We very rarely catch them in such fresh first basic plumage.  In this plumage, the difference in wear between retained juvenal feathers and the recently replaced first basic feathers is very slight.  While extremely subtle (a matter of distinguishing the difference between feathers that differ in age by only a few weeks), there is a discernible molt limit present on her wing (photo below).  As mentioned above in the discussion about the Ovenbird, this warbler followed suit with a molt limit between A1 - the smallest of the three alula feathers - and A2 & A3 (the alula are the three overlaying feathers at the top of the photo above the primary coverts).  All lesser, median, and greater coverts molted along with the carpal and alula covert.  The molted A1 feather is just a bit darker, glossier, and edged more in olive compared to the lower two alula.  As the bird ages and wears the retained juvenal feathers through migration and winter, this molt limit will gradually become more obvious.

 

---

• Tuesday, June 15th - Sunday, June 20th:  We banded four days this week, two of which overlapped the final two days of the Bioforay (see link about the Bioforay below).  75 birds of 28 species were banded with 33 recaps.  We thank Randi Gerrish, Dan Hinnebusch,and Anja Teroerde for their help banding on Wednesday this week.  We began noticing the first occurrence of HY/L (fledgling) birds in any number this week with more than 15 of the birds banded this week being aged as hatching year (HY) or locally hatched (L; equates to very young, i.e., stub-tailed, HY birds, presumably incapable of making sustained long flights).  Three of the new species for the season were also new for the year.  All three were banded on Friday, June 18th:  Northern Rough-winged Swallow (not pictured), Louisiana Waterthrush, and Pileated Woodpecker.

• In recent years, we have regularly caught Louisiana Waterthrushes (LOWA) by early to mid April, so we were delighted to finally catch our first LOWA at the banding lab nearly two months after we first expected to see one in our nets.  In actuality, 43 LOWA's have been banded this year at Powdermill but all have been captured and banded as part of an ongoing study which started out as a focus of LOWAs as bioindicators of stream quality.  Felicity Newell, a recent graduate in Biology from Chatham college, did her internship this spring and has continued into the summer, studying the nesting ecology and success of these birds on two nearby streams.  Under the direction of Bob Mulvihill, who began the study nine years ago,she has been banding (and resighting previously color-banded) adults, nest searching, nest monitoring, and banding nestlings on both Powdermill and Laurel Run this year.  She reports that nesting success for LOWAs along Powdermill Run was very high this year, with eight out of nine pairs successfully fledging young on thier first nesting attempt, the ninth pair failing apparently due to depredation of the female during the incubation phase.  As is usual in this well-forested landscape, cowbird parasitism of LOWA nests was absent.

 
• This second year (SY) female (with brood patch) banded at the lab on Friday was in perfect condition except for having a deformed right foot.  Even more interesting than this likely birth defect, was the impact it had on her efficiency to preen her right side.  She didn't have the ability to balance on her right foot and therefore was unable to preen, in particular, her right wing.  The bottom photos show both her deformed foot and the effect it had on the quality of the feathers on her right wing, proving just how important preening really is for birds in maintaining their feathers.  Compare with the top photo which shows her well preened, and unworn looking left wing.

• Hours after nets were closed for the day, we banded our first Pileated Woodpecker at Powdemill Nature Reserve since 2000.  We thank Jake Mohlmann, one of the crew of Penn State University students living at Powdermill this summer while studying grassland birds, for finding and bringing the hatching year (HY) male PIWO to the banding lab for us to band (and enjoy up close and personal).  The bird was found on one of the local roads about 6 miles from Powdermill.  Although uninjured, it may have been bumped by a passing car, and surely would have been in danger of serious injury if Jake hadn't intervened.  After processing and taking advantage of the opportunity for some photos, Jake returned him to the woods near where it was found, and immediately heard the bird and the rest of its family begin exchanging calls.

Note the male characteristic red feathers beginning to grow in, in the malar streak.

• Tuesday, June 8th - Monday, June 14th:  The 3rd annual Powdermill Bioforay was held from June 11th-June 16th and was a great success this year thanks to the over 30 scientists and other experts and over 20 participants who contributed their help during the six days of the event (click here to read about the Bioforay and results of the bird sampling component from this year).  The banding station was in operation during the Bioforay, but the hot, humid summer weather that persisted throughout the week had an impact on our totals.  We banded only 38 new birds of 17 species with 25 recaps. Randi Gerrish helped with banding this week.

• This unhappy looking immature (SY) male (note the black flecking in front of his eye) American Redstart banded on June 8th was most likely an unsuccessful breeder because he was already well along with his 2nd prebasic (fall molt).  His first three primaries were in pin, as well as, his greater coverts, lesser coverts, and scattered head and body feathers.  Our first Redstart was banded on April 29th, so this bird had likely only been here for about a month when he started undergoing his "fall" molt and will probably be getting ready to migrate south by July.  Talk about a short summer!

 

---

• Tuesday, June 1st - Sunday, June 6th: Nets were open on four mornings this week and a total of 98 birds were banded of 30 species. Randi Gerrish, Dan Hinnebusch, Melissa Jakubcak, Felicity Newell,and Joe Schreiber all helped with banding.

• This week we banded, of course all new species for the season with the start of summer here at Powdermill, but three of them were also new for the year.  The adult (ASY) male Green Heron pictured below was caught on June 1st, the first day of our summer season.  As described in Ralph S. Palmer's Handbook of North American Birds, Volume 1 (published by Yale University Press in 1962), sexes appear similar in all ages.  Like most herons and egrets, however, the soft parts (namely bill, eyes, and/or legs) may acquire brighter colors during the brief span of the breeding season.  The photo on the bottom is a close up of the face, in particular the loral area (the blue soft part in front of the eye). This bird was sexed based on the bright blue lore, glossy black bill, and bright yellow/orange eye.

• We also caught this immature (SY, note the brownish retained juvenal alula and primary coverts) male Cerulean Warbler on the 6th.  Cerulean Warblers are fairly common breeding birds at Powdermill but they nest and generally forage high in the canopy of mature deciduous (oak) forests.  We regularly catch a few each year, usually in summer, when the adults must drop down to care for recently fledged young that have fluttered down to lower levels in the forest and at the forest edge.  In fact, very newly fledged CERWs were observed being fed at eye level in the understroy trees behind our nature center just before our BioForay began.

• Along with the Cerulean Warbler, we caught our first Eastern Wood-Pewee for the year on the 6th of June.  This immature (SY) of unknown sex.

• In addition to the Pileated Woodpecker above, we couldn't resist sharing more of our "baby" pictures from this month, so the photo gallery (click here) for the month of June features the fledgling birds banded at Powdermill Nature Reserve the last few weeks.  Note:  You will have to use your browser back button to return to this page from the link above.

Last Updated on 7/2/04
By Adrienne J. Leppold